A frequency converter includes: a primary winding 12 in which a plurality of windings on which a polyphase alternating voltage is applied are arranged periodically along a particular direction; a secondary winding 22 which is magnetically coupled to the primary winding 12 and in which a plurality of windings are arranged along the particular direction with a repetition period different from the primary winding 12; and a frequency modulation part 3 which is arranged on a magnetic path between the primary winding 12 and the secondary winding 22 and in which a plurality of magnetic materials 31 are arranged periodically. Then, the pitch of the plurality of magnetic materials 31 and the winding arrangement period of the primary winding 12 and the secondary winding 22 are different from each other so that an alternating voltage having a frequency different from the frequency of the polyphase alternating voltage is induced in the secondary winding 22.

A frequency converter includes: a primary winding 12 in which a plurality of windings on which a polyphase alternating voltage is applied are arranged periodically along a particular direction; a secondary winding 22 which is magnetically coupled to the primary winding 12 and in which a plurality of windings are arranged along the particular direction with a repetition period different from the primary winding 12; and a frequency modulation part 3 which is arranged on a magnetic path between the primary winding 12 and the secondary winding 22 and in which a plurality of magnetic materials 31 are arranged periodically. Then, the pitch of the plurality of magnetic materials 31 and the winding arrangement period of the primary winding 12 and the secondary winding 22 are different from each other so that an alternating voltage having a frequency different from the frequency of the polyphase alternating voltage is induced in the secondary winding 22.

A solid state power transformer is described for converting an input power signal at a first phase or voltage to an output signal of a second voltage or opposite phase by the use of bidirectional solid state switches switched at a high carrier frequency to produce a double-sideband, suppressed-carrier representation of the input power signal, which is then synchronously demodulated using further similar switches to produce the desired output. It is further disclosed that multiple instances of the above with relative phase-staggering of the switching frequency may be operated in parallel and activated or deactivated according to output current demand to provide maximum efficiency over a wide range of current and power levels.

The invention provides a subsea pressure boosting system feasible for operation at subsea step out lengths above 40 km and by control merely from a dry topside or onshore location. The system is distinctive in that it comprises: at least one subsea power step out cable, arranged from a near end at a dry location onshore or topsides to one or more subsea loads such as subsea pumps or subsea compressors at a far end, at the near end at least one source for electric power is connected and the cable is dimensioned for operation at a frequency different from the operation frequency of the connected subsea loads in order to handle the Ferranti effect and electric losses, and at least one passive electric frequency transformer, operatively connected between the subsea step out cable far end and the subsea loads, said transformer is located in a pressure vessel and transforms the operation frequency of the subsea step out cable to a frequency feasible for operation of the connected loads.

A solid state power transformer is described for converting an input power signal at a first phase or voltage to an output signal of a second voltage or opposite phase by the use of bidirectional solid state switches switched at a high carrier frequency to produce a double-sideband, suppressed-carrier representation of the input power signal, which is then synchronously demodulated using further similar switches to produce the desired output. It is further disclosed that multiple instances of the above with relative phase-staggering of the switching frequency may be operated in parallel and activated or deactivated according to output current demand to provide maximum efficiency over a wide range of current and power levels.

A method for transferring electrical power in the sea includes generating AC power, guiding, at least partially underwater, the AC power through a cable from a first end of the cable to a second end of the cable, and changing a frequency of the AC power guided through the cable based on a value of power consumption of a load connected to the second end of the cable.

A method for transferring electrical power in the sea includes generating AC power, guiding, at least partially underwater, the AC power through a cable from a first end of the cable to a second end of the cable, and changing a frequency of the AC power guided through the cable based on a value of power consumption of a load connected to the second end of the cable.

A converter device configured to exchange power between a first grid and a second grid, including a first inverter configured to connect on an AC side thereof to the first grid, and connected on a DC side thereof to a link circuit of the converter device, and a second inverter configured to connect on an AC side thereof to the second grid, and connected on a DC side thereof to the link circuit. The converter device also includes a solar generator connected to the link circuit, a first controller operably coupled to the first inverter and configured to set a specified converter power of the first inverter, and a second controller operably coupled to the second inverter and configured to set a voltage of the link circuit such that a power of the solar generator optimized according to a predetermined criteria.

A converter device configured to exchange power between a first grid and a second grid, including a first inverter configured to connect on an AC side thereof to the first grid, and connected on a DC side thereof to a link circuit of the converter device, and a second inverter configured to connect on an AC side thereof to the second grid, and connected on a DC side thereof to the link circuit. The converter device also includes a solar generator connected to the link circuit, a first controller operably coupled to the first inverter and configured to set a specified converter power of the first inverter, and a second controller operably coupled to the second inverter and configured to set a voltage of the link circuit such that a power of the solar generator optimized according to a predetermined criteria.

Provided are voltage and frequency transformation systems, methods and devices, and relate to the field of transformers. The method includes: inputting low-frequency electric energy with frequency lower than a first predetermined frequency threshold; the low-frequency electric energy including low-frequency and low-voltage electric energy or low-frequency and high-voltage electric energy; obtaining high-frequency electric energy with frequency higher than a second predetermined frequency threshold; the high-frequency electric energy including first high-frequency and low-voltage electric energy or first high-frequency and high-voltage electric energy; obtaining second high-frequency electric energy after voltage transformation; the second high-frequency electric energy including second high-frequency and high-voltage electric energy or second high-frequency and low-voltage electric energy; obtaining second low-frequency electric energy; the second low-frequency electric energy including second low-frequency and high-voltage electric energy or second low-frequency and low-voltage electric energy.